I hope Alucard employs the Master Librarian to help with all that stuff in the belmont library. Maybe even look after it while he takes his centuries long nap.
You never know, that how we may get the Alucard spear in the Netflix universe, by mixing the counts knowledge of science and magic, and the Belmont's knowledge of hunting and magic. I think that be cool. as I always believed that the Alucard made the spear, by texts he found in the his family's book of secret arts.
So i thought in the TV show, it be cool if he made the spear from a mix of both, a nice way to call back to it but give it a new life too.
Ad thinking about it Gandolfi most likely used other stuff he found in the book, to make the armour he sold, and on a bigger note, maybe others used stuff from that book. So that why stuff like holy armour and what not, find there way into the castle as there maybe a link.
As the stuff you sometimes find there seem to work against the counts plans.
But that's just what i think.